Floor covering for covering removable floor panels, floor construction with floor covering, and method for production of the floor covering

ABSTRACT

There is described a floor covering ( 6 ) for covering removable floor panels ( 1 ), especially of raised floors. To minimize laying costs, there is uniformly applied on the underside of the floor covering ( 6 ) a conductive fixing adhesive ( 2 ) that has been air-cured to ready-to-lay condition and that is protected externally against drying out by a backing film ( 7 ).

[0001] The invention relates to a floor covering, especially for raisedfloors, according to the preamble of claim 1, as well as to a floorconstruction comprising removable floor panels covered with the floorcovering, according to the preamble of claim 5, and to a method forproduction of an inventive floor covering, according to the preamble ofclaim 12.

[0002] Raised or installation floors are used in order to create asecond plane that can support foot traffic or other loads above thesubfloor of a room. Between the building's subfloor or bare floor andthis second plane there is created a clear void space, which can then beused for installation or laying of cables, pipes, air ducts, etc.

[0003] The plane for supporting foot traffic or other loads is verygenerally constructed from individual, usually square supports or floorpanels, which are braced relative to the building floor via a pluralityof pedestals or underground structures and on the upper side are linedwith floor-covering tiles, which are fixed to the support panels inslip-proof manner by means of fixing adhesive.

[0004] For this purpose it must be ensured that the floor-covering tilescan be removed without problems, in order to permit easy access to theunderfloor installation for the purpose of undertaking maintenancetasks. It must therefore be possible to loosen the fixative easily andwithout destroying it, and so a permanent bond is out of the question.

[0005] Additional requirements are imposed on the fixative, such asprovision of a conductive layer, in order thereby to prevent leakage ofelectrostatic charges that may build up on the surface or to ensure thatsuch charges are conducted to ground.

[0006] Further requirements include ease of laying and good stability ofthe floor-covering tiles against slipping.

[0007] For this purpose a coat of fixing adhesive, known as a“tackifier”, is commonly applied on the laid base or support panels. Anexample is Thomsit T425 tackifier of the Henkel Co. or Forbo-Antirutsch541 [Forbo anti-slip compound 541], on which the floor-covering tilescan be laid without becoming permanently bonded but without danger ofslipping after a required setting time of about 30 to 120 minutes haselapsed. The fixing adhesive is based, for example, on an acrylatedispersion, into which an additional conductive additive has beenintermixed to ensure the desired conductivity.

[0008] The problems which commonly occur during the laying of floorcoverings described in the foregoing can be explained by referring hereand now to FIG. 1, which shows a schematic overhead view of a raisedfloor.

[0009] It is evident that no adhesive is applied in the region of thejoints (gap A in FIG. 1) between the support panels. As can be inferredfrom FIG. 1, it is only in this way that bonding of the support panelsto one another can be avoided and the necessary easy access to theunderfloor region can be ensured.

[0010] On the whole, therefore, the installation of such a floor islaborious, time-consuming and mistake-prone:

[0011] Once the base construction containing the floor panels has beenlaid, the fixing adhesive must be applied. In this process, care must betaken that, if at all possible, no adhesive is applied in the region ofthe abutting joints. On the other hand, sufficient adhesive must beapplied in the region of the corners of the base panels, as shown inFIG. 1, in order to fix the floor-covering tiles adequately and toprovide a continuous, conductive layer.

[0012] Thereafter the applied coat of fixing adhesive must be hardenedor set; during this period, further processing is not possible. Thenecessary hardening time depends on ambient conditions such asatmospheric humidity, temperature, surface of the floor panels, etc. andis therefore difficult to determine. Thus an unnecessary waste of timecan result if the adhesive has already set, or—which is a much worseproblem—the floor-covering tiles have become undesirably bonded to thesupport panels of the floor, so that the floor-covering tiles can nolonger be lifted up thereafter without damaging them.

[0013] Finally, the floor-covering tiles must be laid without destroyingthe fixative and conductive layer, for example by excessive foottraffic. Thus the floor-covering tiles must be laid on the slip-proofadhesive, which can be achieved only with the skill of a craftsman.

[0014] Because of the difficulties outlined in the foregoing, the entirelaying process must therefore be performed manually by appropriatelytrained, skilled craftsmen, thus leading to high costs.

[0015] Starting from this problem, the object is therefore to provide anappropriately pretreated floor covering, whereby the floor-coveringlaying procedure can be streamlined and the particularly time-consumingand mistake-prone process step of applying the adhesive or tackifier canbe separated out from the laying process to be performed manually andachieved in a single process that can be performed externally and inadvance by machinery, so that the floor can be installed inexpensivelyand precisely on the whole, even by less well trained personnel.

[0016] This object is achieved for the floor covering by the features ofclaim 1, for the overall floor construction by the features of claim 5,and for the method for production of the inventive floor covering by thefeatures of claim 12, in the form of an individual process separated outfrom the laying process.

[0017] By means of a floor covering pretreated according to theinvention with antistatic fixing adhesive applied in ready-to-laycondition on its underside, it is possible to achieve a considerableincrease in efficiency during installation of an inventive floor. Theadhesive coat is applied on a floor covering according to claim 1 andthen allowed to set such that it can be laid without the development offorces of cohesion and without bonding. In addition, it is protected bya film, so that excessive drying out of the conductive or antistaticfixing adhesive is prevented and the desired adhesive effect ispreserved until the floor-covering tiles have been laid.

[0018] A requirement often imposed on a floor, namely that thedevelopment of electrostatic charges due to friction on a floor actingas an insulating layer be prevented, or that such an effect becompensated by grounding via the floor, can be met in simple manneraccording to claim 2 by using a tackifier with antistatic effect,obtained from an acrylate dispersion providing the desired adhesivefunctionality and an intermixed electrically conductive additive.

[0019] A satisfactory antistatic effect is achieved, for example, withcarbon, in the form of carbon black, for example, intermixed as anelectrically conductive additive in a proportion of about 25% in thetackifier based on an acrylate dispersion. Obviously other substances orsubstance mixtures having the desired adhesive and/or antistaticproperties can be used in the scope of the invention.

[0020] A special additional advantage of the invention is achieved whenretrofit operations such as the laying of cable runs are undertaken inthe floor under the floor panels. In such a case the floor covering mustbe lifted off and the floor-covering panels removed and stacked off tothe side. Heretofore the electricians have usually walked on the barefloor while performing laying tasks, thus inevitably picking up dust onthe soles of their shoes and tracking it onto the exposed adhesivesurface when they step out of the duct. This problem is effectivelyeliminated with the inventive structure of the floor covering. Because,according to the invention, the floor panels are no longer treated withadhesive, they can be simply vacuumed on completion of the retrofit ormodification tasks. The undamaged floor covering, for example in theform of covering tiles with underside coating, can be relaid withoutimpairment of their function.

[0021] Finally, a further advantage of the invention becomes clear whenthe floor covering has to be replaced. Because, according to theinvention, the floor covering is not permanently bonded to the basecourse, such as floor topping, no part of the base course, such as floortopping, is torn up during replacement of the covering, and so there iseffectively no need for troweling work. Furthermore, no residualadhesives, which heretofore had to be ground off, are left there. Thisopens up the opportunity to use the inventive technique with all itsadvantages even when floor coverings sold by the meter are being laid.

[0022] Furthermore, the inventive floor covering can be produced in asimple method according to claim 12. Because the environmentalparameters are adjustable, the setting time of the applied tackifiercoat can be precisely maintained and its coat thickness can be keptconstant at the optimal value, so that the desired functionality of theadhesive coat as a tackifier but not as a bonding agent is achieved withgreat reliability. The method can also be performed as a continuousprocess, thus allowing further cost reductions to be achieved.

[0023] The floor covering according to claim 1 offers the furtheradvantage that, when packaged according to claim 13 in the form of rollsaccording to claim 3, it is suitable both for direct laying in hand-cutsections and as a commercial precursor product, which can be thestarting material for other commercial products in the form of variouslysized floor-covering tiles according to claim 4, without the need forchangeover times on appropriate machines during its production. Thus,from the floor covering, which can also be sold by the meter,ready-to-lay floor-covering tiles according to claim 4 can be producedby a single operation, in which the floor covering is divided in amanner to be adjusted to the desired tile size, or floor-covering tilesare stamped out from the floor covering by the method the according toclaim 14.

[0024] Furthermore, there is no longer any need to take special carewith the butt joints of the floor layout or of the laid floor panelsduring laying of the inventive floor covering or floor-covering tiles,since the adhesive or tackifier is largely hardened or set. The risk ofbonding of the base panels of the floor to one another is thereforeeffectively ruled out, and the function of an inventive floorconstruction, especially of a raised floor according to claim 5, inorder to provide an installation space that is rapidly accessible butconcealed from view, can be achieved with great reliability and littletime expenditure.

[0025] Furthermore, better adhesion of the floor covering to the floorpanels is also achieved in this way, since the floor covering isuniformly coated with tackifier. Thus adhesion of the floor covering tothe floor panels is ensured even in the regions of the butt joints ofthe base panels, without the risk that the floor panels will becomebonded to one another, since the fixing adhesive has already set by thetime of the laying operation.

[0026] Particularly good adhesion is achieved when the floor coveringaccording to claim 6 is laid in such a way that it overlaps the buttjoints of the base panels. This is achieved in a particularly simple waywhen, according to claim 7, its size is different from that of the floorpanels.

[0027] According to claim 8, the fixing-adhesive coat continues toadhere to the floor covering and is not transferred to the floor panelswhen the floor covering is lifted up to gain access to the underfloor.Specifically, the fixative coat bonds to the floor covering during theinventive production method and must have a natural cohesion that isstronger than the force of adhesion between the adhesive coat and thefloor panels.

[0028] This can be accompanied by measures such as provision of a smoothsurface according to claim 9 or of an appropriate upper-side coatingaccording to claim 10 or of impregnation of the floor panels accordingto claim 11.

[0029] The individual features of the embodiments according to theclaims can be combined as desired if it seems technically practical.

[0030] Preferred embodiments of the invention will be explained in moredetail hereinafter on the basis of schematic drawings, wherein:

[0031]FIG. 1 shows a schematic overhead view of a conventional raisedfloor during the laying operation, FIG. 2a shows a sectional side viewof a conventional raised floor with applied fixing adhesive, but withoutfloor covering, FIG. 2b shows a sectional side view of an inventiveraised floor,

[0032]FIG. 3 shows a sectional side view of an inventive floor covering,

[0033]FIG. 4 shows a perspective view of an inventive floor-coveringroll,

[0034]FIG. 5 shows a schematic view of an inventive raised floor.

[0035] The procedure for laying of conventional floor-covering tiles ona floor panel forming a raised-floor plane is evident in FIG. 1. A coatof fixing adhesive is applied on floor panels disposed flush with oneanother along corresponding butt joints 3 and resting via theirrespective corners on one quarter of the surface of round pedestalheads. Region A along butt joints 3 is left clear, but fixing adhesiveis again applied at the corners of the panels. Some floor-covering tilesthat have already been laid are indicated by hatched areas.

[0036]FIG. 2a shows a section of a conventional raised floor while thetackifier is setting. A pedestal head 4 is seated on a pedestal 5. Floorpanels 1 rest via their respective corners on pedestal head 4. Betweenpanels 1 there are disposed joints 3, in the area of which (see gap A)no adhesive 2 is applied, in contrast to the rest of the upper side ofthe floor panels. After hardening or setting of the adhesive,conventional floor-covering tiles can be applied thereon.

[0037] In contrast to this, in the section of an inventive raised floorshown in FIG. 2b, floor covering 6 with fixing adhesive 2 applied on itsunderside is already laid on floor panels 1, and so joints 3 are alsooverlapped with adhesive coat 2. The floor panels are braced viapedestal heads 4, to the underside of which there are joined pedestals5. In this way a rapidly accessible clear void space for ventilationshafts, network installations, etc. is provided underneath the floorpanels.

[0038] As covering for the floor panels there is used floor covering 6,which is illustrated in FIG. 3 and which has a continuously appliedadhesive coat 7 protected by a film 7 that can be easily peeled off.

[0039]FIG. 4 shows a floor covering 6 rolled up as a roll 6 b ready forretail. Floor-covering tiles 6 a to be punched out are also indicated bybroken lines on a portion that has now been unrolled.

[0040] For comparison with the conventionally laid raised floor shown inoverhead view in FIG. 1, there is shown in FIG. 5 a raised floorinstalled using inventive floor-covering tiles 6 b (indicated bydot-dash lines): The pedestal heads denoted by 4 support floor panels 1,on which there are fixed floor-covering tiles 6 b with fixing adhesive 7applied flatly on the underside thereof (see FIGS. 2b, 3). By means ofbroken lines there is also shown a ventilation shaft 11, which runs inthe void space between the plane of the floor panels and the plane ofthe base floor (such as the concrete slab) and is supposed to be keptaccessible. It is also evident that floor-covering tiles 6 b have a sizewhich is different from (larger than) that of floor panels 1, thuslargely ensuring that joints 3 between floor-covering panels 1 areoverlapped by floor-covering tiles 6 a.

[0041] Modifications of the illustrated versions are obviously possiblewithout going beyond the basic ideas of the invention. From theforegoing description it follows that the floor covering, such as thefloor-covering tiles, does not have to be cut to match the pattern inwhich the floor panels are laid. In other words, the pattern of theraised-floor panels can be, but is not required to be, identical to thatof the coated floor-covering tiles.

1. A floor covering (6) for covering removable floor panels (1),especially of raised floors, characterized in that there is uniformlyapplied on the underside of the floor covering (6) a conductive fixingadhesive (2) that has been air-cured to ready-to-lay condition and thatis protected externally against drying out by a backing film (7).
 2. Afloor covering (6) according to claim 2, characterized in that anacrylate dispersion containing an electrically conductive additive isused as the fixing adhesive (7).
 3. A floor covering (6) according toclaim 1 or 2, in the form of a floor-covering roll (6 a).
 4. A floorcovering (6) according to one of claims 1 to 3, in the form offloor-covering tiles (6 b).
 5. A floor construction, especially a raisedfloor, in which a floor covering (6) according to one of claims 1 to 4is laid on a layer of floor panels (1) disposed flush with one another.6. A floor construction according to claim 5, characterized in that thefloor covering (6) overlaps the butt joints (3) between the floor panels(1) laid flush with one another.
 7. A floor construction according toclaim 5 or 6 with floor-covering tiles (6 b) according to claim 3,characterized in that the floor covering (6 b) has a size different fromthat of the floor panels (1).
 8. A floor construction according to oneof claims 5 to 7, characterized in that the adhesion of the fixingadhesive (2) to the floor covering (6) is stronger than to the floorpanels (1).
 9. A floor construction according to one of claims 5 to 8,characterized in that the floor panels (1) are finished with a smoothsurface on the upper side.
 10. A floor construction according to one ofclaims 5 to 9, characterized in that the floor panels (1) are finishedwith a smooth coating on the upper side.
 11. A floor constructionaccording to one of claims 5 to 10, characterized in that the floorpanels (l) are finished with an impregnation on the upper side.
 12. Amethod for production of a floor covering (6) according to one of claims1 to 3, characterized in that it comprises the following process steps:application of a conductive fixing adhesive (2) onto the floor covering(6), air-curing of the floor covering (6) provided with the conductivefixing adhesive (2), the air-curing time (TL) being chosen such that theadhesive (2) sets sufficiently that the natural cohesion is strongerthan the force of adhesion to a backing film (7) to be subsequentlyapplied, protection of the conductive fixing adhesive (2) with thebacking film (7), which can be peeled off without residues.
 13. A methodaccording to claim 12 for production of a floor covering (6) accordingto claim 3, characterized in that the floor covering (6) is then rolledup and packaged as commercial floor-covering rolls (6 a).
 14. A methodaccording to claim 12 for production of a floor covering (6) accordingto claim 4, characterized in that the floor-covering tiles (6 b) aresubsequently punched out of the floor covering (6).